Fuel consumption down from 30 to 22

[SilverVti]

Hi

  I've been running my Vti from new in 1998 and have tracked fuel consumption since the start (yeah I know ). Fuel consumption has consistently averaged 31/30 from the start until a around 2-3 years ago when consumption dropped gradually to 23/24 mpg where it has remained ever since.

  I've not done a lot of miles in recent years but it's been used regularly. I did reset the ECU in 2010 but it made no difference.

Any suggestions on how to restore fuel consumption other than to check plugs and get a new engine ??

Thanks in advance.

SilverVti 

[Krzys]

You can get pattern OE exhaust parts but not sure how good a CAT would be from a motor factors.

[Dexter]

On 18.6.2016 at 4:12 PM, Dexter said:

I failed MOT due to high CO and the path lead to a burnt distributor cap & rotor.

 

Sorry my bad! The High CO% was cured by changing the O2-sensor. High HC was the rotor & cap.

[SilverVti]

I've taken the polunge and have a complete system ready to go on the car. The sum total of the parts was £ 130 including all new bolts, springs, rubber mounts and gaskets. 

 

After having a runaround with Euro Car parts I've got a BM Catalysts BM90551 which is a pattern part and non type approved. It was just over £40 !!!  BM supply manufacturers, and Euro Car parts under the Euro car parts sub-brand React. It sounds like a cat is a cat, certainly for this age car. Type approved cats are required for cars sold after 2001 which  need a more expensive version that has more precious metals in it. Also on some newer cars a sensor AFTER the cat allows the ECU to measure whether the cat is working or not (by comparing O2/lamba readings going into and out of the cat) This Civic doesn't hjave that so there is no way to check the cat is working other than changing it and seeing if the readings improve.

 

If they do, then happy days - If they don't I guess it means I have an engine in need of attention. However based on how well it runs, I'm not expecting that. Fingers crossed. 

I haven't changed the distributor and rotor and the HC wasn't high in any case. I haven't changed the O2 sensor as the readings are fine coming out of the exhaust.  

 

The Honda service manual doesn't give all the info I've needed, and exhaust systems whether it be Klarius/Arvin/Timax or BM Catalysts also don't correctly list all of the parts - eg the gasket between the replacement cat and mid section was a tricky one. If anyone needs a set of part numbers I can post it.

 

Anyway, I'm gonna get my hands dirty tomorrow - I'll report back as to how it goes !

 

More reading ..... there is a short explanation of how cats work here http://www.bmcatalysts.co.uk/technical-information/

and here about O2 sensors http://www.autotap.com/techlibrary/understanding_oxygen_sensors.asp

and here about you can see what emissions your car is meant to meet looking at the government handbook here 

https://www.gov.uk/government/publications/in-service-exhaust-emission-standards-for-road-vehicles-18th-edition

 

 

 

 

 

[noodels]

Checked the valve clearance recently?

[SilverVti]

Never.  That's a head off job isn't it? Sounds pricy and beyond my skills.  

How bout compression test -  would that be an easier first step? 

[Krzys]

Just the rocker cover off to check valve clearance.

 

My Type R has the secondary sensor after the CAT you mentioned.

[SilverVti]

Well that was pretty straightforward.  About an hour with a local independent mechanic,  job done.  

Seems to have a good sound,  not larey,  not blowy.  Certainly pongs a bit  and nice silver coloured exhaust now coating the exit of the tail pipe.  

We didn't get as far as valves or disty. The mechanic felt if it was valves that would be suggested by sluggish starting -  which isn't a problem.

I'll give it a few weeks to settle in and will then re-check emissions probably at MOT time. Should also have a better view of fuel consumption by then too. 

Ta for the tips guys. 

 

[kalvtec]

How did this go mate any update?